1. Field of the Invention
A temperature control system for use with a fluid circulating system operable in a heating or cooling state to control the temperature and flow of fluid circulated through a remote liquid circulating manifold.
2. Description of the Prior Art
Thermal blanklets and heating pads are well known in the art. Such thermal blankets commonly include either a cooling or heating effect. Generally heating blankets or pads incorporated the use of electrical resistance elements disposed thereout the area of the blanket. Similarly cold applicator pads or blankets used in the medical field frequently include a flexible plastic package containing two chemicals which when mixed together absorb heat. The chemicals are frequently packaged on either side of a rupturable membrane so that application of pressure to the exterior package ruptures the membrane and causes the fluids to mix and produces the heat absorbing reaction. Alternately, cooling pads may be used in combination with a compressor, refrigerant condensation and evaporator coils. It is obvious that the above type cold pads or blankets are heavy and cumbersome.
With reference to heat type thermal blankets used in the medical field, structures have been developed to circulate a heated fluid through a duct in the pad or blanket. Such structure are designed to overcome the obvious inefficiencies and disadvantages associated with the structures involving heating resistance wires embedded in the blanket or pad.
It is recognized that the use of fluid in a both a heating and cooling thermal blanket or pad is much desirable over the aforementioned prior art structures. However such a structure does include certain disadvantages. U.S. Pat. No. 3,894,213 to Kumar and Brown and U.S. Pat. No. 3,967,627 are examples of prior art structures which while operational appear to be bulky, less than reliable and do not have certain safeguards involved with the application of selected and variable temperature ranges which would be highly desirable. In contrast, U.S. Pat. No. 4,459,468 discloses a circulating system capable of producing both a heated and cooled fluid of various temperatures circulated to the thermal blanket at the desired "hot" or "cold" temperature. The system comprises a reservoir and a temperature transfer means to heat or cool fluid within the reservoir. A temperature sensor monitors the fluid temperature in the reservoir. A temperature control means is electrically connected in current regulating and activating relation to the temperature transfer means such that a continuous path of information flows between the monitored fluid and temperature control means and to the thermal modules for activation thereof in order to maintain the desired temperature.